The invention relates in general to mining and in particular to a new and useful system for the supply of extraction machines in mining operations with the operating means necessary for its operation such as electric energy, hydraulic or gaseous media.
The extraction machines are moved back and forth in a longwall of a mine at the working face and are, as a rule, guided at the longwall conveyor. The drive of the extraction machine is effected either by pulling means driven from the longwall end or by a drive integrated into the extraction machine. For feeding the driving and operating means there are different solutions. Thus, among others, the energy carrying lines are dragged along and deposited by the extraction machine in a cable conduit disposed at the longwall conveyor on the stowage side. It is then customary to deposit the lines singly or bundled within a flexible cable chain. Further it is known to feed the energy carrying lines in loops to the extraction machine by means of a cable carriage guided in a side timber duct of the longwall conveyor and provided with guide rollers for the lines. The drive of the cable carriage is effected by the extraction machine or by reels set up at the longwall end as a function of the movement of the extraction machine.
At low propulsion speeds of the extraction machine (about 0.1 m/sec), an orderly disposition of the drag lines will still be possible with the first named method. But at higher propulsion speeds this becomes a problem. The relatively high movement resistance of the drag line sliding on the stationary base leads to a short life of the lines. Frequent bending of the lines below the minimum radii increases the danger of fatigue breakes, especially when the longwalls are low. The use of cable drag chains leads to considerable additional noise in the mining operations. Furthermore, also the extracted material collecting in the cable conduit open at the top constitutes a hindrance to proper cable guiding. In addition to the disadvantages mentioned in connection with a drag chain guiding, jerky load applications may occur with the loop type cable guiding, which lead to a strong lateral and/or vertical swinging of the line strands locally. For this reason, sufficiently high timbers must be provided for the formation of the cable conduit, which are an obstacle to their use in relatively low veins.